Year 1 - After grazing an area, a deposit is left by an animal. The grass grows in response to the dung, which causes selective grazing to occur. Then the response occurs as the grass regrows where it was grazed from and the rejection of the grass near the dung continues.
Year 2 - The response continues and then so does the rejection of the grass by the dung. However, after the next regrowth occurs, the rejection ceases and normal grazing begins again.